It is time that Muslims and Christians recognized just how similar they are  the fate of the world depends on it. That's the message being sent out today by 138 Muslim leaders and scholars in an open letter to their Christian counterparts saying that world peace hinges on greater understanding between the two faiths.

The 29-page letter  entitled "A Common Word between Us and You"  is addressed to Pope Benedict XVI, Archbishop of Canterbury Rowan Williams and 25 other named Christian leaders and "Leaders of Christian Churches, everywhere". Organized by the Royal Aal al-Bayt Institute for Islamic Thought in Amman, Jordan, it's the first time so many high-profile Muslims have come together to make such a public call for peace. Launched first in Jordan this morning, and then in other countries over the course of the day, the letter gets its final unveiling at a joint press conference in Washington, D.C., this afternoon by Mustafa Ceric, Grand Mufti of Bosnia, and John Esposito, director of the Prince Alwaleed Bin Talal Center for Muslim-Christian Understanding at Georgetown University. By pointing out the similarities between the Bible and the Koran, between Christianity and Islam, the letter's signatories are asking Christian leaders to "come together with us on the common essentials of our two religions."

The signatories include Sheik Mohammed Nur Abdullah, vice president of the Fiqh Council of North America; Sheikh Salem Falahat, director-general of the Muslim Brotherhood in Jordan; Hasan Shariatmadari, head of the Iranian National Republicans party; and Sheikh Ikrima Said Sabri, former Grand Mufti of Jerusalem and Imam of Al-Aqsa Mosque. "This is a determination by mainstream, traditional Muslim scholars and authorities who cover all the branches of Islam, and that's very unusual," says David Ford, Director of the Inter-Faith Program at the University of Cambridge, who helped launch the letter in London this morning. "It is unapologetic  but not aggressive, not defensive  and is genuinely hospitable in all directions. It's also modest. It doesn't claim to be the final word; it's 'a' common word."

Quoting from both holy texts, the letter notes that "whilst Islam and Christianity are obviously different religions  and whilst there is no minimizing some of their formal differences," both require believers to believe in only one god, and it's the same god. It points out that both religions are founded on goodwill, not violence, and that many of the fundamental truths that were revealed to Muhammad  such as the necessity for the total devotion to God, the rejection of false gods, and the love of fellow human beings  are the same ones that came to other Christian and Jewish prophets.

Because of this, the letter says, Muslims are duty-bound by the Koran to treat believers of other faiths with respect and friendship  and that Muslims expect the same in return. "As Muslims, we say to Christians that we are not against them and that Islam is not against them  as long as they do not wage war against Muslims on account of their religion, oppress them and drive them out of their homes."

With Christians making up about 33% of the world's population and Muslims making up around 22%, the letter says that finding common ground, "is not simply a matter for polite ecumenical dialogue between selected religious leaders." Is it, instead, essential for the survival of humanity. "The relationship between these two religious communities [is] the most important factor in contributing to meaningful peace around the world. If Muslims and Christians are not at peace, the world cannot be at peace. No side can unilaterally win a conflict between more than half of the world's inhabitants. Thus our common future is at stake. The very survival of the world itself is perhaps at stake."

This letter comes on the anniversary of another open letter to the Pope last year, which was signed by 38 Muslim clerics and was response to a speech on Islam in which the Pope quoted a medieval text saying it is a violent religion: "Show me just what Muhammad brought that was new and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." The Pope later apologized, saying that he had only used the quote  an opinion which he said he doesn't share  to condemn violence motivated by religion and to highlight the need for exchange and understanding between the faiths.

Now Islamic leaders have come together again to try and make that happen. "This is the way forward," says Ford. "To combine Muslim solidarity around core teachings together with friendly address to Christians and respect for the public good as a whole." The letter ends with a quote from the Koran  "Vie one with another in good works ... Unto God ye will all return, and He will then inform you of that wherein ye differ"  before making a final plea for peace: "So let our differences not cause hatred and strife between us. Let us vie with each other only in righteousness and good works." Surely that's a sentiment people of all faiths can share.